| Titre | Methodology for solute characterization of fluid inclusions by petrographic and SEM/EDS complementary analysis |
| Télécharger | Téléchargements |
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| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Tweedale, F; Hanley, J J; Kontak, D J; Rogers, N |
| Source | TGI 4 - Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation; par Rogers, N (éd.); Commission géologique du Canada, Dossier public 7843, 2015 p. 569-570, https://doi.org/10.4095/296495  Accès ouvert |
| Liens | Canadian Database of Geochemical Surveys, downloadable files
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| Liens | Banque de données de levés géochimiques du Canada,
fichiers téléchargeables
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| Image |  |
| Année | 2015 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/296495 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans TGI 4 -
Intrusion Related Mineralisation Project: new vectors to buried porphyry-style mineralisation |
| Formats | pdf |
| Province | Nouvelle-Écosse |
| SNRC | 21A; 11D; 11E |
| Lat/Long OENS | -66.0000 -63.5000 45.0000 43.0000 |
| Sujets | gisements porphyriques; cuivre porphyrique; prospection minière; minéralisation; altération; tungstène; molybdène; étain; bismuth; gisements minéraux; roches intrusives; roches granitiques; inclusions
fluides; analyses pétrographiques; granodiorites; pétrogenèse; cuivre; or; Batholite de South Mountain ; géologie économique; minéraux métalliques; pétrologie ignée et métamorphique |
| Illustrations | cartes de localisation; photomicrographies; graphiques; diagrammes ternaires |
| Programme | Initiative géoscientifique ciblée (IGC-4) Étude des gîtes porphyriques |
| Diffusé | 2015 06 11; 2023 03 17 |
| Résumé | (disponible en anglais seulement)
A cost-effective, simple, and time-efficient method to determine the bulk composition of fluid inclusions is evaporate mound analysis. This method is
semi-quantitative and determines inclusion composition by integrating SEM imaging with energy-dispersive analysis of precipitates, or mounds, produced by thermal decrepitation of fluid-inclusions. The method is applicable to magmatic-hydrothermal
systems where fluid inclusions contain solute ions (e.g., Na, K, Ca, Cl, F). In order to assess the application of this method for evaluating hydrothermal evolution and metal fertility with regards to intrusion-related mineralisation, a test study is
being conducted on the large (7800 km2) and variably mineralized (e.g., Sn, W, Cu, U, Mo, Ta) South Mountain Batholith (SMB) of Nova Scotia.
Decrepitate mounds were analyzed using a LEO 1450VP (SEM) imaging system linked to an Oxford X-Max 80 mm2
SDD detector energy-dispersive detector. Based on decrepitating over a range of temperatures, from 325°C to 500°C, it appears that T = 500°C is optimal to produce large, well-shaped, and readily identifiable mounds. To optimize analysis time and,
hence, increase research efficiency while maintaining result accuracy, data were collected with 5, 10, and 30 second acquisition times. The number of analyses required to produce representative results was also tested by comparing the results for 4,
8, 16, 32, and 64 mound analyses for individual samples. Results indicate that optimal procedures require multiple (N = 12) point-mode analyses on individual decrepitate mounds to substantiate mound heterogeneity, and that in order to accurately
reflect in-situ fractionation a single, 10 second raster-mode analysis is the best approach.
These optimal analytical protocols are being applied to a regional study of the SMB to determine their suitability as mineral fertility indicator and/or
vector to ore mineralisation. This test case is the first of its kind conducted on a batholithic scale, with the resulting methodological protocols being readily exportable for the mineral fertility assessment of other regions. Data interpretation
protocols integrate a granitic petrographic alteration index, fluid inclusion types, density and evaporate mound chemistry. Samples are chosen such that the entire batholith may be assessed, with all mapped lithologies represented. Fluid compositions
determined thus far include brines with 5-20 % fluorine, which is quantitatively indeterminable using other methods, and has been linked as primary control on the transport and deposition of ore in porphyry- and greisen-style
mineralisation. |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'Initiative géoscientifique ciblée (IGC-4) est un programme géoscientifique fédéral de collaboration qui fournit à l'industrie les
connaissances géoscientifiques et les techniques novatrices de prochaine génération dont elle a besoin pour mieux détecter les gîtes minéraux enfouis, réduisant ainsi certains risques liés à l'exploration. Ce volume résume les activités de recherche
effectuées dans le cadre du projet de minéralisation lié à des intrusions de l'Initiative géoscientifique ciblée 4 qui était axé sur des systèmes minéralisés porphyriques associés aux dépôts de Cu et de Cu-Mo dans le centre-sud de la
Colombie-Britannique et aux dépôts de Sn-W-Mo-In au Nouveau-Brunswick, en Nouvelle-Écosse et à Terre-Neuve-et-Labrador. |
| GEOSCAN ID | 296495 |
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